当你点击 Make Directory as -> Excluded 时，

Android Studio中的文件夹不见，我找了半天

最后发现在

 在工程名+app.main.iml 会有：
<excludeFolder url="file://$MODULE_DIR$/../../../../../../../../Share/JavaCode/JavaPlatform/Code/JavaPlatform/Book/Algorithms" />
<excludeFolder url="file://$MODULE_DIR$/../../../../../../../../Share/JavaCode/JavaPlatform/Code/JavaPlatform" /

  

 

 删除这两行重新编译文件夹就出现了。

<excludeFolder url="file://$MODULE_DIR$/../../../../../../../../Share/JavaCode/JavaPlatform/Code/JavaPlatform/Book/Algorithms" />
<excludeFolder url="file://$MODULE_DIR$/../../../../../../../../Share/JavaCode/JavaPlatform/Code/JavaPlatform" /